CD11c+ B cells in relapsing-remitting multiple sclerosis and effects of anti-CD20 therapy

OBJECTIVES

B cells are important in the pathogenesis of multiple sclerosis. It is yet unknown which subsets may be involved, but atypical B cells have been proposed as mediators of autoimmunity. In this study, we investigated differences in B-cell subsets between controls and patients with untreated and anti-CD20-treated multiple sclerosis.

METHODS

We recruited 155 participants for an exploratory cohort comprising peripheral blood and cerebrospinal fluid, and a validation cohort comprising peripheral blood. Flow cytometry was used to characterize B-cell phenotypes and effector functions of CD11c+ atypical B cells.

RESULTS

There were no differences in circulating B cells between controls and untreated multiple sclerosis. As expected, anti-CD20-treated patients had a markedly lower B-cell count. Of B cells remaining after treatment, we observed higher proportions of CD11c+ B cells and plasmablasts. CD11c+ B cells were expanded in cerebrospinal fluid compared to peripheral blood in controls and untreated multiple sclerosis. Surprisingly, the proportion of CD11c+ cerebrospinal fluid B cells was higher in controls and after anti-CD20 therapy than in untreated multiple sclerosis. Apart from the presence of plasmablasts, the cerebrospinal fluid B-cell composition after anti-CD20 therapy resembled that of controls. CD11c+ B cells demonstrated a high potential for both proinflammatory and regulatory cytokine production.

INTERPRETATION

The study demonstrates that CD11c+ B cells and plasmablasts are less efficiently depleted by anti-CD20 therapy, and that CD11c+ B cells comprise a phenotypically and functionally distinct, albeit heterogenous, B-cell subset with the capacity of exerting both proinflammatory and regulatory functions.

Sustained effects on immune cell subsets and autoreactivity in multiple sclerosis patients treated with oral cladribine

Introduction

Cladribine tablet therapy is an efficacious treatment for multiple sclerosis (MS). Recently, we showed that one year after the initiation of cladribine treatment, T and B cell crosstalk was impaired, reducing potentially pathogenic effector functions along with a specific reduction of autoreactivity to RAS guanyl releasing protein 2 (RASGRP2). In the present study we conducted a longitudinal analysis of the effect of cladribine treatment in patients with RRMS, focusing on the extent to which the effects observed on T and B cell subsets and autoreactivity after one year of treatment are maintained, modulated, or amplified during the second year of treatment.

Methods

In this case-control exploratory study, frequencies and absolute counts of peripheral T and B cell subsets and B cell cytokine production from untreated patients with relapsing-remitting MS (RRMS) and patients treated with cladribine for 52 (W52), 60 (W60), 72 (W72) and 96 (W96) weeks, were measured using flow cytometry. Autoreactivity was assessed using a FluoroSpot assay.

Results

We found a substantial reduction in circulating memory B cells and proinflammatory B cell responses. Furthermore, we observed reduced T cell responses to autoantigens possibly presented by B cells (RASGRP2 and a-B crystallin (CRYAB)) at W52 and W96 and a further reduction in responses to the myelin antigens myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) after 96 weeks.

Conclusion

We conclude that the effects of cladribine observed after year one are maintained and, for some effects, even increased two years after the initiation of a full course of treatment with cladribine tablets.

Immune reconstitution following alemtuzumab therapy is characterized by exhausted T cells, increased regulatory control of proinflammatory T cells and reduced B cell control

Alemtuzumab is a monoclonal antibody targeting CD52 on the surface of immune cells, approved for the treatment of active relapsing-remitting multiple sclerosis (RRMS). The purpose of this study was to analyze the repopulation of peripheral lymphocytes following alemtuzumab-induced lymphocyte depletion and investigate associations with disease activity and development of secondary autoimmunity. For this, blood samples were collected two years after initiation of alemtuzumab treatment and lymphocytes were subjected to a comprehensive flow cytometry analysis. Included in the study were 40 patients treated with alemtuzumab and 40 treatment-naïve patients with RRMS. Disease activity and development of secondary autoimmune disease was evaluated after three years of treatment. Our study confirms that alemtuzumab treatment profoundly alters the circulating lymphocyte phenotype and describes a reconstituted immune system characterized by T cell activation/exhaustion, an increased regulatory control of IL-17 producing effector T cells and CD20+ T cells, and a reduced control of B cells. There were no obvious associations between immune cell subsets and disease activity or development of secondary autoimmune disease during treatment with alemtuzumab. Our results indicate that the reconstituted immune response is skewed towards a more effective regulatory control of MS-associated proinflammatory T cell responses. Also, the enlarged pool of naïve B cells together with the apparent decrease in control of B cell activity may explain why alemtuzumab-treated patients retain the ability to mount a humoral immune response towards new antigens.

Cladribine Effects on T and B Cells and T Cell Reactivity in Multiple Sclerosis

OBJECTIVE

Cladribine tablet therapy is an efficacious treatment for multiple sclerosis (MS), however, its mechanism of action on T and B cell subsets remains unclear. The purpose of this study was to investigate the treatment effects of cladribine on the peripheral pool of T and B cells subsets and reactivity toward central nervous system (CNS) antigens.

METHODS

In this cross-sectional exploratory study, frequencies and absolute counts of peripheral T and B cell subsets and B cell cytokine production from untreated patients with relapsing-remitting MS (RRMS) and patients treated with cladribine for 1 year were measured using flow cytometry. Autoreactivity was assessed using a FluoroSpot assay.

RESULTS

We found that 1 year after initiation of cladribine treatment, a lower number of CD4+ T cells was persisting whereas CD19+ B cell counts were normalized compared to untreated patients with RRMS. Follicular helper T cells and their effecter subsets producing cytokines exerting distinct B cell helper activity were lower and, additionally, the peripheral B cell pool was skewed toward a naïve and anti-inflammatory phenotype. Finally, reactivity to the recently identified CNS-enriched autoantigen RAS guanyl-releasing protein 2 (RASGRP2), but not to myelin basic protein and myelin oligodendrocyte glycoprotein, was lower in cladribine-treated patients.

INTERPRETATION

Together, these investigations on T and B cell subsets suggest that cladribine treatment impairs the B-T cell crosstalk and reduces their ability to mediate pathogenic effector functions. This may result in specific reduction of autoreactivity to RASGRP2 which is expressed in B cells and brain tissue. ANN NEUROL 2023;94:518-530.

Relationship between cerebrospinal fluid biomarkers of inflammation and tissue damage in primary progressive multiple sclerosis

BACKGROUND AND OBJECTIVES

It is unclear to what extent intrathecal inflammation contributes to the pathogenesis in primary progressive multiple sclerosis (PPMS). We conducted an exploratory study to investigate the degree of intrathecal inflammation and its association with biomarkers of disease activity and severity in patients with PPMS.

METHODS

We included patients with PPMS who participated in a randomized controlled trial conducted at the Danish Multiple Sclerosis Center, patients with relapsing-remitting multiple sclerosis (RRMS) and healthy controls. We analyzed concentrations of a panel of cytokines in CSF using electrochemiluminescence assays. We then explored the relationship between cytokines found in increased CSF concentrations in patients with PPMS (compared with healthy controls) with CSF concentrations of neurofilament light chain (NFL) and myelin basic protein (MBP), IgG-index, and magnetic resonance imaging (MRI) metrics (volume, magnetization transfer ratio and diffusion tensor imaging) from lesions, normal-appearing white matter, and cortical grey matter.

RESULTS

We included 59 patients with PPMS, 40 patients with RRMS, and 21 healthy controls. In patients with PPMS, CSF concentrations of CC chemokine ligand 3 (CCL-3), CXC chemokine ligand 8 (CXCL-8), CXCL-10, interleukin (IL)-10, IL-15, and vascular endothelial growth factor (VEGF)-A were increased compared with healthy controls and comparable with CSF concentrations in patients with RRMS. In addition, patients with PPMS had increased CSF concentrations of IL-12p40, IL-17A, tumor necrosis factor (TNF)-α, and lymphotoxin (LT)-α compared with healthy controls, but concentrations of these cytokines were even higher in patients with RRMS. For the remaining seven cytokines (CCL22, interferon-γ, IL-5, IL-7, IL-16, IL-22, IL-27), we found no difference between patients with PPMS and healthy controls. CSF concentrations of NFL and MBP correlated weakly with concentrations of IL-15, while the remaining proinflammatory cytokines were not associated with CSF concentrations of NFL or MBP. The IgG-index correlated with four cytokines (IL-10, IL-12p40, TNF-α, and LT-α). We did not observe any significant associations between MRI metrics and CSF biomarkers of inflammation.

DISCUSSION

In this exploratory study, we found few and weak associations between intrathecal inflammation and the extent of neuroaxonal damage and demyelination, and no associations between intrathecal inflammation and MRI metrics, in patients with PPMS. Our findings suggest that, for patients with PPMS, these measures of intrathecal inflammation are not associated with the extent of neuroaxonal injury, demyelination, and disease severity, and these processes may therefore have less relevance in PPMS than in relapsing forms of MS.

Increased Intrathecal Activity of Follicular Helper T Cells in Patients With Relapsing-Remitting Multiple Sclerosis

BACKGROUND AND OBJECTIVES

Follicular helper T (Tfh) cells play a critical role in protective immunity helping B cells produce antibodies against foreign pathogens and are likely implicated in the pathogenesis of various autoimmune diseases. The purpose of this study was to investigate the role of Tfh cells in the pathogenesis of multiple sclerosis (MS).

METHODS

Using flow cytometry, we investigated phenotype, prevalence, and function of Tfh cells in blood and CSF from controls and patients with relapsing-remitting MS (RRMS) and primary progressive MS (PPMS). In addition, an in vitro blood-brain barrier coculture assay of primary human astrocytes and brain microvascular endothelial cells grown in a Boyden chamber was used to assess the migratory capacity of peripheral Tfh cells.

RESULTS

This study identified 2 phenotypically and functionally distinct Tfh cell populations: CD25^- Tfh cells (Tfh1-like) and CD25^int Tfh cells (Tfh17-like). Whereas minor differences in Tfh cell populations were found in blood between patients with MS and controls, we observed an increased frequency of CD25^- Tfh cells in CSF of patients with RRMS and PPMS and CD25^int Tfh cells in patients with RRMS, compared with controls. Increasing frequencies of CSF CD25^- Tfh cells and the CD25^- Tfh/Tfr ratio scaled with increasing IgG index in patients with RRMS. Despite an increased prevalence of intrathecal Tfh cells in patients with MS, no difference in the migratory capacity of circulating Tfh cells was observed between controls and patients with MS. Instead, CSF concentrations of CXCL13 scaled with total counts of Tfh and Tfr cell subsets in the CSF.

DISCUSSION

Our study indicates substantial changes in intrathecal Tfh dynamics, particularly in patients with RRMS, and suggests that the intrathecal inflammatory environment in patients with RRMS promotes recruitment of peripheral Tfh cells rather than the Tfh cells having an increased capacity to migrate to CNS.

Ofatumumab Modulates Inflammatory T Cell Responses and Migratory Potential in Patients With Multiple Sclerosis

BACKGROUND AND OBJECTIVES

The anti-CD20 antibody ofatumumab is an efficacious therapy for multiple sclerosis (MS) through depletion of B cells. The purpose of this study was to examine the derivative effects of B cell depletion on the peripheral immune system and a direct treatment effect on T cells expressing CD20.

METHODS

Frequency and absolute numbers of peripheral leukocytes of treatment-naive patients with relapsing-remitting MS (RRMS) and patients treated with ofatumumab for a mean of 482 days were assessed in this observational study by flow cytometry. In addition, effector function and CNS migration of T cells using a human in vitro blood-brain barrier (BBB) assay were analyzed.

RESULTS

This study showed that ofatumumab treatment of patients with RRMS increased the control of effector T cells and decreased T cell autoreactivity. It also showed that ofatumumab reduced the level of peripheral CD20⁺ T cells and that the observed decrease in CNS-migratory capacity of T cells was caused by the depletion of CD20⁺ T cells. Finally, our study pointed out a bias in the measurement of CD20⁺ cells due to a steric hindrance between the treatment antibody and the flow cytometry antibody.

DISCUSSION

The substantial ofatumumab-induced alteration in the T cell compartment including a severely decreased CNS-migratory capacity of T cells could partly be attributed to the depletion of CD20⁺ T cells. Therefore, we propose that depletion of CD20⁺ T cells contributes to the positive treatment effect of ofatumumab and suggests that ofatumumab therapy should be considered a B cell and CD20⁺ T cell depletion therapy.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that compared with treatment-naive patients, ofatumumab treatment of patients with RRMS decreases peripheral CD20⁺ T cells, increases effector T cell control, and decreases T cell autoreactivity.

Peripheral helper T cells in the pathogenesis of multiple sclerosis

BACKGROUND

Peripheral helper T cells (Tph) are likely implicated in the pathogenesis of various inflammatory diseases. Tph cells share functions with follicular helper T cells, including plasma cell differentiation and antibody production.

OBJECTIVE AND METHODS

To investigate a possible role of Tph cells in the pathogenesis of multiple sclerosis (MS), we used flow cytometry to analyze the function, phenotype, and central nervous system (CNS)-recruitment of Tph cells in the blood and cerebrospinal fluid (CSF) from controls and patients with relapsing-remitting (RR) and primary progressive (PP) MS.

RESULT

This study identified two functionally distinct Tph cell populations and a regulatory counterpart, Tpr cells. No differences in blood frequencies, cytokine production, or potential to interact with B cells were found between controls and patients with MS. Along with an equal CNS-migration potential, we found both Tph cell populations enriched in the CSF; and surprisingly, an increased frequency of intrathecal Tph cells in the control group compared to patients with MS.

CONCLUSION

Altogether, we did not find an increased frequency of CSF Tph cells in patients with RRMS or PPMS. Our findings indicate that rather than being involved in MS pathogenesis, Tph cells may be implicated in normal CNS immunosurveillance.

Dimethyl Fumarate Treatment in Patients With Primary Progressive Multiple Sclerosis: A Randomized, Controlled Trial

Background and Objective

To study whether dimethyl fumarate is superior to placebo in decreasing CSF concentrations of neurofilament light chain (NFL) in patients with primary progressive MS (PPMS).

Methods

In the double-blind, placebo-controlled phase 2 study dimethyl FUMArate treatment in Progressive Multiple Sclerosis (FUMAPMS), patients with PPMS were randomly assigned to treatment with 240 mg dimethyl fumarate or placebo in a 1:1 ratio for 48 weeks. The primary endpoint was change in concentration of NFL in the CSF. Secondary endpoints included other CSF biomarkers and clinical and MRI measures. Efficacy was evaluated for the full data set by multiple imputations to account for missing data. Safety was assessed for the full data set.

Results

Fifty-four patients (mean age 54.9 years [SD 6.1], median Expanded Disability Status Scale 4.0 [nterquartile range 4.0–6.0], disease duration 14.1 [SD 9.4], and 21 [39%] female) were randomized to either placebo (n = 27) or dimethyl fumarate (n = 27) therapy. At screening CSF concentrations, adjusted for age and sex, of NFL, myelin basic protein (MBP), soluble CD27, chitinase 3-like 1, and B-cell maturation antigen were higher than in a group of symptomatic controls. Twenty-six patients (96%) in the dimethyl fumarate group and 24 patients (89%) in the placebo group completed the randomized phase. Mean change in CSF concentrations of NFL did not differ between groups (mean difference 99 ng/L; 95% CI −292 to 491 ng/L). MBP in CSF decreased in the treatment group (−182 ng/L, 95% CI −323 to −41 ng/L compared with placebo). The difference observed in the multiple imputation data set was not significant in a per protocol analysis. This was nominally significant in the multiple imputation data set but not in the per protocol analysis This was not found in the per protocol analysis Other secondary and tertiary outcomes were not affected. Various infections, lymphopenia, flushing, and gastrointestinal side effects were more frequent in the dimethyl fumarate group. Serious adverse events were similar between groups.

Discussion

Dimethyl fumarate treatment for 48 weeks had no effect on any of the investigated efficacy measures in patients with PPMS. We did not observe adverse events not anticipated for dimethyl fumarate treatment.

Trial Registration Information

Clinicaltrials.gov identifier NCT02959658.

Classification of Evidence

This study provides Class I evidence that for patients with PPMS, dimethyl fumarate treatment has no effect on CSF NFL levels compared with placebo treatment.

MAIT cell subtypes in multiple sclerosis

In patients with multiple sclerosis (MS) and healthy controls (HC) we studied circulating MAIT cells and MAIT cell subtypes expressing CXCR3 and CCR6 by flow cytometry. Absolute numbers of MAIT cells and specifically Tc17-like MAIT cells were lower in patients with primary progressive MS (PPMS) than in controls. Low numbers of Tc17-like MAIT cells were associated with smoking and high concentrations of myelin basic protein in the cerebrospinal fluid. Treatment with alemtuzumab and dimethyl fumarate decreased MAIT cell frequencies. Altogether, we have identified specific MAIT cell subtypes related to PPMS, smoking and demyelination, and MAIT cell effects of MS therapies.

Dimethyl fumarate therapy reduces memory T cells and the CNS migration potential in patients with multiple sclerosis

BACKGROUND

Dimethyl fumarate (DMF) is a disease-modifying therapy for patients with relapsing-remitting multiple sclerosis (RRMS). T cells are major contributors to the pathogenesis of RRMS, where they regulate the pathogenic immune response and participate in CNS lesion development.

OBJECTIVES

In this study we evaluate the therapeutic effects of DMF on T cell subpopulations, their CNS migration potential and effector functions.

METHODS

Blood and CSF from untreated and DMF-treated patients with RRMS and healthy donors were analyzed by flow cytometry.

RESULTS

DMF reduced the prevalence of circulating proinflammatory CD4+ and CD8+ memory T cells, whereas regulatory T cells were unaffected. Furthermore, DMF reduced the frequency of CD4+ T cells expressing CNS-homing markers. In coherence, we found a reduced recruitment of CD4+ but not CD8+ T cells to CSF. We also found that monomethyl fumarate dampened T cell proliferation and reduced the frequency of TNF-α, IL-17 and IFN-γ producing T cells.

CONCLUSION

DMF influences the balance between proinflammatory and regulatory T cells, presumably favoring a less proinflammatory environment. DMF also reduces the CNS migratory potential of CD4+ T cells whereas CD8+ T cells are less affected. Altogether, our study suggests an anti-inflammatory effect of DMF mainly on the CD4+ T cell compartment.

Dimethyl fumarate therapy suppresses B cell responses and follicular helper T cells in relapsing-remitting multiple sclerosis

Background:

Dimethyl fumarate (DMF) is a disease-modifying therapy used for patients with relapsing-remitting multiple sclerosis (RRMS). B cells are important contributors to the pathogenesis of RRMS, where they regulate the inflammatory immune responses and participate in development of lesions in the central nervous system (CNS). The impact of DMF on B cell subpopulations remains incompletely understood.

Objectives:

In this study, we evaluated the effects of DMF on B cell subpopulations and their effector functions.

Methods:

Blood from 21 DMF-treated and 18 untreated patients with RRMS was analyzed by flow cytometry.

Results:

We found that DMF reduces the frequency of circulating antigen–experienced B cells, a reduction likely related to a reduced frequency of follicular helper T (TFH) cells and an increased frequency of follicular regulatory T (TFR) cells. Studying the impact of monomethyl fumarate (MMF), the primary metabolite of DMF, on B cell effector function in vitro showed that MMF increased the frequency of transforming growth factor (TGF)-β-producing B cells and decreased the frequency of B cells secreting lymphotoxin (LT)-α, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and to a lesser extent IL-10.

Conclusion:

In summary, these data suggest an anti-inflammatory role of DMF and its metabolite MMF on the B cell compartment.

Quantum logic gates and nuclear magnetic resonance pulse sequences

There has recently been considerable interest in the use of nuclear magnetic resonance (NMR) as a technology for the implementation of small quantum computers. These computers operate by the laws of quantum mechanics, rather than classical mechanics and can be used to implement new quantum algorithms. Here we describe how NMR in principle can be used to implement all the elements required to build quantum computers, and draw comparisons between the pulse sequences involved and those of more conventional NMR experiments.

Snowblower injuries to the hand

When operated carelessly, snowblowers can produce serious trauma to the hand. During a 3-year period, 13 cases were identified. The injuries occurred when the operators attempted to dislodge impacted snow from the snowblower chute. Experience with the equipment did not appear to be a factor. The frequency of injuries was directly related to the depth of snowfall. Higher temperatures and wet snow were also important. The long and ring fingers of the dominant hand were most frequently injured. A total of 22 digits in 13 patients were involved. Three digits underwent amputation. All patients had fractures, ranging from simple closed fractures of the distal tuft to open comminuted fractures of the proximal phalanx. Injuries were treated with debridement and primary repair. Operator carelessness is usually responsible for the injury. If the public is made aware of snowblower hazards at the time of heavy snowfall, injuries may be avoided.

Foreign body granuloma and synovitis of the finger: a hazard of ring removal by the sawing technique

A case of chronic digital synovitis and foreign body reaction secondary to metallic filings is reported. The patient had a digital mass and a previous history of a ring finger injury. A saw action ring remover was implicated as a source of foreign bodies produced by ring removal over the open wound. Care should be taken to avoid implantation of metal filings with this technique, and an alternate method of removing rings from injured fingers should be considered.

Seven-digit replantation: digit survival after 39 hours of cold ischemia

A patient who has undergone successful replantation of seven of eight amputated digits is presented. Survival in the last viable digit was seen 39 hours after amputation with cold ischemia preservation. No graded ischemia-related changes in the digits have been appreciated over 35 months of follow-up.

Major injuries due to agricultural machinery

Agricultural accidents are a frequent cause of severe injury. Sixty-four patients with such injuries were seen from October 1981 through September 1984. The patients ranged in age from 2 to 73 years. The highest incidence of injury occurred during spring planting (May through June) and fall harvesting (September through October). The tractor and grain auger were the most common injuring agents. The upper extremity was the most common site of injury, followed by the lower extremity. Because such injuries are usually of a crushing nature and are heavily contaminated, extensive debridement and irrigation are essential in their care.

A comprehensive retraining program for inactive medical technologists

Shortage of laboratory personnel appears to have created growing interest and activity in retraining inactive medical technologists. A recent three year program at the University of Wisconsin involving 63 individuals enrolled in one or more courses provides some results. Twenty-three are now employed, and nine are actively seeking employment. The development, presentation, evaluation and cost of the program are here reported.

Model course for retraining inactive medical technologists

In the belief that there is an ongoing need for the retraining of inactive medical technologists, the University of Wisconsin-Madison initiated such a program in 1978. A model course in routine chemistry and instrumentation was developed, presented, and evaluated. This model is described in detail. Results indicate that most inactive medical technologists can regain competence. The program and individual courses are designed so they can be easily replicated or adapted for use by others interested in retraining inactive medical tehcnologists.

External fixation of endotracheal tubes while skin grafting severe burns of the face

The use of an external cranial device for endotracheal tube fixation can prevent mechanical dislodgement of skin grafts and permit easy access while one is operating on extensive burns of the face.